Since there has been interest in my story I'll tell another part of it. When we first discovered the distributor was copying us we sent them a letter telling them we had a patent and to stop. It did no good.

When we met with the lawyers they told us we made a big mistake. We were admitting we knew about the infringement. This sealed the issue of losing the patent. If we had acted ignorant we could have argued later we didn't know about it.